scholarly journals The Phosphatidylserine Receptor TIM-1 Enhances Authentic Chikungunya Virus Cell Entry

Cells ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 1828
Author(s):  
Jared Kirui ◽  
Yara Abidine ◽  
Annasara Lenman ◽  
Koushikul Islam ◽  
Yong-Dae Gwon ◽  
...  
Keyword(s):  
Chikungunya Virus ◽  
Molecular Mechanisms ◽  
Rna Virus ◽  
Ectopic Expression ◽  
Point Mutations ◽  
Cell Entry ◽  
Target Cells ◽  
Human Hepatoma Cells ◽  
Chikv Infection ◽  
Phosphatidylserine Receptor

Chikungunya virus (CHIKV) is a re-emerging, mosquito-transmitted, enveloped positive stranded RNA virus. Chikungunya fever is characterized by acute and chronic debilitating arthritis. Although multiple host factors have been shown to enhance CHIKV infection, the molecular mechanisms of cell entry and entry factors remain poorly understood. The phosphatidylserine-dependent receptors, T-cell immunoglobulin and mucin domain 1 (TIM-1) and Axl receptor tyrosine kinase (Axl), are transmembrane proteins that can serve as entry factors for enveloped viruses. Previous studies used pseudoviruses to delineate the role of TIM-1 and Axl in CHIKV entry. Conversely, here, we use the authentic CHIKV and cells ectopically expressing TIM-1 or Axl and demonstrate a role for TIM-1 in CHIKV infection. To further characterize TIM-1-dependent CHIKV infection, we generated cells expressing domain mutants of TIM-1. We show that point mutations in the phosphatidylserine binding site of TIM-1 lead to reduced binding, entry, and infection of CHIKV. Ectopic expression of TIM-1 renders immortalized keratinocytes permissive to CHIKV, whereas silencing of endogenously expressed TIM-1 in human hepatoma cells reduces CHIKV infection. Altogether, our findings indicate that, unlike Axl, TIM-1 readily promotes the productive entry of authentic CHIKV into target cells.

scholarly journals Ribavirin and Alpha Interferon Enhance Death Receptor-Mediated Apoptosis and Caspase Activation in Human Hepatoma Cells

2003 ◽  
Vol 47 (6) ◽  
pp. 1912-1921 ◽  
Author(s):  
Stephan F. Schlosser ◽  
Markus Schuler ◽  
Christoph P. Berg ◽  
Kirsten Lauber ◽  
Klaus Schulze-Osthoff ◽  
...  
Keyword(s):  
Hepg2 Cells ◽  
Molecular Mechanisms ◽  
Caspase 3 ◽  
Death Receptor ◽  
Alpha Interferon ◽  
Target Cells ◽  
Clinical Effects ◽  
Caspase Activation ◽  
Human Hepatoma Cells ◽  
Promoting Effect

ABSTRACT The molecular mechanisms underlying the clinical effects of alpha interferon (IFN) and ribavirin are not understood. Elimination of infected cells occurs in part by cytotoxic T lymphocytes (CTLs) expressing CD95 ligand and thereby attacking target cells which are positive for the death receptor CD95. Since many viruses have evolved mechanisms to inhibit apoptosis, the opposite, namely, promotion of apoptosis, could be a strategy to strengthen the host antiviral response. In the present study, we have asked whether the antiviral substances IFN and ribavirin could support CD95-mediated apoptosis by interfering with the activation of caspases, a family of proteases known for their essential role in apoptosis. HepG2 cells, stimulated with the agonistic anti-CD95 antibody, served as a minimal model to mimic the CD95 stimulation ocurring during a CTL attack of target cells in vivo. Apoptosis was quantitated by flow cytometric detection of hypodiploid nuclei. Caspase activity was measured by cytofluorometry, immunocytochemistry, and immunoblot analysis. IFN and ribavirin sensitized HepG2 cells for CD95-mediated apoptosis. This effect was correlated with an increase in CD95-mediated caspase activation and enhanced cleavage of the caspase substrate poly(ADP-ribose) polymerase. Furthermore, the positive effect on CD95-mediated caspase activation by IFN and ribavirin was confirmed by immunocytochemistry for activated caspase-3 and by immunoblot detection of activated caspase-3, caspase-7, and caspase-8. Our data demonstrate that the antiviral substances IFN and ribavirin are able to sensitize for CD95-mediated apoptosis. IFN and ribavirin also enhance CD95-mediated caspase activation, which might in part be responsible for the apoptosis-promoting effect of these antiviral compounds.

scholarly journals Serotonergic Drugs Inhibit Chikungunya Virus Infection at Different Stages of the Cell Entry Pathway

2020 ◽  
Vol 94 (13) ◽  
Author(s):  
Ellen M. Bouma ◽  
Denise P. I. van de Pol ◽  
Ilson D. Sanders ◽  
Izabela A. Rodenhuis-Zybert ◽  
Jolanda M. Smit
Keyword(s):  
Membrane Fusion ◽  
Mechanism Of Action ◽  
Economic Burden ◽  
Serotonin Receptor ◽  
Chikungunya Virus ◽  
Replication Cycle ◽  
Cell Entry ◽  
Chikv Infection ◽  
Potential Host ◽  
Serotonergic Drugs

ABSTRACT Chikungunya virus (CHIKV) is an important reemerging human pathogen transmitted by mosquitoes. The virus causes an acute febrile illness, chikungunya fever, which is characterized by headache, rash, and debilitating (poly)arthralgia that can reside for months to years after infection. Currently, effective antiviral therapies and vaccines are lacking. Due to the high morbidity and economic burden in the countries affected by CHIKV, there is a strong need for new strategies to inhibit CHIKV replication. The serotonergic drug 5-nonyloxytryptamine (5-NT) was previously identified as a potential host-directed inhibitor for CHIKV infection. In this study, we determined the mechanism of action by which the serotonin receptor agonist 5-NT controls CHIKV infection. Using time-of-addition and entry bypass assays, we found that 5-NT predominantly inhibits CHIKV in the early phases of the replication cycle, at a step prior to RNA translation and genome replication. Intriguingly, however, no effect was seen during virus-cell binding, internalization, membrane fusion and genomic RNA (gRNA) release into the cell cytosol. In addition, we show that the serotonin receptor antagonist methiothepin mesylate (MM) also has antiviral properties toward CHIKV and specifically interferes with the cell entry process and/or membrane fusion. Taken together, pharmacological targeting of 5-HT receptors may represent a potent way to limit viral spread and disease severity. IMPORTANCE The rapid spread of mosquito-borne viral diseases in humans puts a huge economic burden on developing countries. For many of these infections, including those caused by chikungunya virus (CHIKV), there are no specific treatment possibilities to alleviate disease symptoms. Understanding the virus-host interactions that are involved in the viral replication cycle is imperative for the rational design of therapeutic strategies. In this study, we discovered an antiviral compound, elucidated its mechanism of action, and propose serotonergic drugs as potential host-directed antivirals for CHIKV.

scholarly journals Serotonergic drugs inhibit CHIKV infection at different stages of the cell entry pathway

2020 ◽  
Author(s):  
Ellen M. Bouma ◽  
Denise P.I. van de Pol ◽  
Ilson D. Sanders ◽  
Izabela A. Rodenhuis-Zybert ◽  
Jolanda M. Smit
Keyword(s):  
Membrane Fusion ◽  
Mechanism Of Action ◽  
Economic Burden ◽  
Serotonin Receptor ◽  
Chikungunya Virus ◽  
Replication Cycle ◽  
Cell Entry ◽  
Chikv Infection ◽  
Potential Host ◽  
Serotonergic Drugs

AbstractChikungunya virus (CHIKV) is an important re-emerging human pathogen transmitted by mosquitoes. The virus causes an acute febrile illness, chikungunya fever, which is characterized by headache, rash and debilitating (poly)arthralgia that can reside for months to years after infection. Currently, effective antiviral therapies and vaccines are lacking. Due to the high morbidity and economic burden in the countries affected by CHIKV, there is a strong need for new strategies to inhibit CHIKV replication. The serotonergic drug, 5-nonyloxytryptamine (5-NT), was previously identified as a potential host-directed inhibitor for CHIKV infection. In this study, we determined the mechanism of action by which the serotonin receptor agonist 5-NT controls CHIKV infection. Using time-of-addition and entry bypass assays we found that 5-NT predominantly inhibits CHIKV in the early phases of the replication cycle; at a step prior to RNA translation and genome replication. Intriguingly, however, no effect was seen during virus-cell binding, internalization, membrane fusion and gRNA release into the cell cytosol. Additionally, we show that the serotonin receptor antagonist MM also has antiviral properties towards CHIKV and specifically interferes with the cell entry process and/or membrane fusion. Taken together, pharmacological targeting of 5-HT receptors may represent a potent way to limit viral spread and disease severity.ImportanceThe rapid spread of mosquito-borne viral diseases in humans puts a huge economic burden on developing countries. For many of these infections, including Chikungunya virus (CHIKV), there are no specific treatment possibilities to alleviate disease symptoms. Understanding the virus:host interactions that are involved in the viral replication cycle is imperative for the rational design of therapeutic strategies. In this study, we discovered an antiviral compound and elucidated the mechanism of action and propose serotonergic drugs as potential host-directed antivirals for CHIKV.

scholarly journals Genome-Wide Screening Uncovers the Significance of N-Sulfation of Heparan Sulfate as a Host Cell Factor for Chikungunya Virus Infection

2017 ◽  
Vol 91 (13) ◽  
Author(s):  
Atsushi Tanaka ◽  
Uranan Tumkosit ◽  
Shota Nakamura ◽  
Daisuke Motooka ◽  
Natsuko Kishishita ◽  
...  
Keyword(s):  
Virus Infection ◽  
Heparan Sulfate ◽  
Chondroitin Sulfate ◽  
Chikungunya Virus ◽  
Yellow Fever Virus ◽  
Host Cells ◽  
Pseudotyped Virus ◽  
Target Cells ◽  
Chikv Infection ◽  
Genome Wide

ABSTRACT The molecular mechanisms underlying chikungunya virus (CHIKV) infection are poorly characterized. In this study, we analyzed the host factors involved in CHIKV infection using genome-wide screening. Human haploid HAP1 cells, into which an exon-trapping vector was introduced, were challenged with a vesicular stomatitis virus pseudotype bearing the CHIKV E3 to E1 envelope proteins. Analysis of genes enriched in the cells resistant to the pseudotyped virus infection unveiled a critical role of N-sulfation of heparan sulfate (HS) for the infectivity of the clinically isolated CHIKV Thai#16856 strain to HAP1 cells. Knockout of NDST1 that catalyzes N-sulfation of HS greatly decreased the binding and infectivity of CHIKV Thai#16856 strain but not infectivity of Japanese encephalitis virus (JEV) and yellow fever virus (YFV). While glycosaminoglycans were commonly required for the efficient infectivity of CHIKV, JEV, and YFV, as shown by using B3GAT3 knockout cells, the tropism for N-sulfate was specific to CHIKV. Expression of chondroitin sulfate (CS) in NDST1-knockout HAP1 cells did not restore the binding of CHIKV Thai#16856 strain and the infectivity of its pseudotype but restored the infectivity of authentic CHIKV Thai#16856, suggesting that CS functions at later steps after CHIKV binding. Among the genes enriched in this screening, we found that TM9SF2 is critical for N-sulfation of HS and therefore for CHIKV infection because it is involved in the proper localization and stability of NDST1. Determination of the significance of and the relevant proteins to N-sulfation of HS may contribute to understanding mechanisms of CHIKV propagation, cell tropism, and pathogenesis. IMPORTANCE Recent outbreaks of chikungunya fever have increased its clinical importance. Chikungunya virus (CHIKV) utilizes host glycosaminoglycans to bind efficiently to its target cells. However, the substructure in glycosaminoglycans required for CHIKV infection have not been characterized. Here, we unveil that N-sulfate in heparan sulfate is essential for the efficient infection of a clinical CHIKV strain to HAP1 cells and that chondroitin sulfate does not help the CHIKV binding but does play roles at the later steps in HAP1 cells. We show, by comparing previous reports using Chinese hamster ovary cells, along with another observation that enhanced infectivity of CHIKV bearing Arg82 in envelope E2 does not depend on glycosaminoglycans in HAP1 cells, that the infection manner of CHIKV varies among host cells. We also show that TM9SF2 is required for CHIKV infection to HAP1 cells because it is involved in the N-sulfation of heparan sulfate through ensuring NDST1 activity.

scholarly journals New Insights into Chikungunya Virus Infection and Pathogenesis

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Vasiliya Kril ◽  
Olivier Aïqui-Reboul-Paviet ◽  
Laurence Briant ◽  
Ali Amara
Keyword(s):  
Chikungunya Virus ◽  
Molecular Mechanisms ◽  
Clinical Manifestations ◽  
Annual Review ◽  
Publication Date ◽  
Nonstructural Proteins ◽  
Chikv Infection ◽  
Replication Complex ◽  
Host Cell Interactions ◽  
Patients Experience

Chikungunya virus (CHIKV) is a re-emerging mosquito-borne alphavirus responsible for major outbreaks of disease since 2004 in the Indian Ocean islands, South east Asia, and the Americas. CHIKV causes debilitating musculoskeletal disorders in humans that are characterized by fever, rash, polyarthralgia, and myalgia. The disease is often self-limiting and nonlethal; however, some patients experience atypical or severe clinical manifestations, as well as a chronic rheumatic syndrome. Unfortunately, no efficient antivirals against CHIKV infection are available so far, highlighting the importance of deepening our knowledge of CHIKV host cell interactions and viral replication strategies. In this review, we discuss recent breakthroughs in the molecular mechanisms that regulate CHIKV infection and lay down the foundations to understand viral pathogenesis. We describe the role of the recently identified host factors co-opted by the virus for infection and pathogenesis, and emphasize the importance of CHIKV nonstructural proteins in both replication complex assembly and host immune response evasion. Expected final online publication date for the Annual Review of Virology, Volume 8 is September 2021. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

scholarly journals Silvestrol Inhibits Chikungunya Virus Replication

Viruses ◽  
2018 ◽  
Vol 10 (11) ◽  
pp. 592 ◽  
Author(s):  
Lisa Henss ◽  
Tatjana Scholz ◽  
Arnold Grünweller ◽  
Barbara Schnierle
Keyword(s):  
Chikungunya Virus ◽  
Therapeutic Strategy ◽  
Rna Virus ◽  
Specific Inhibitor ◽  
Rna Replication ◽  
Host Protein ◽  
Untranslated Regions ◽  
Interferon Α ◽  
Innate Response ◽  
Chikv Infection

Silvestrol, a natural compound that is isolated from plants of the genus Aglaia, is a specific inhibitor of the RNA helicase eIF4A, which unwinds RNA secondary structures in 5′-untranslated regions (UTRs) of mRNAs and allows translation. Silvestrol has a broad antiviral activity against multiple RNA virus families. Here, we show that silvestrol inhibits the replication of chikungunya virus (CHIKV), a positive single-stranded RNA virus. Silvestrol delayed the protein synthesis of non-structural (nsPs) and structural proteins, resulting in a delayed innate response to CHIKV infection. Interferon-α induced STAT1 phosphorylation was not inhibited nor did eIF2α become phosphorylated 16 h post infection in the presence of silvestrol. In addition, the host protein shut-off induced by CHIKV infection was decreased in silvestrol-treated cells. Silvestrol acts by limiting the amount of nsPs, and thereby reducing CHIKV RNA replication. From our results, we propose that inhibition of the host helicase eIF4A might have potential as a therapeutic strategy to treat CHIKV infections.

scholarly journals Tyro3 Family-Mediated Cell Entry of Ebola and Marburg Viruses

2006 ◽  
Vol 80 (20) ◽  
pp. 10109-10116 ◽  
Author(s):  
Masayuki Shimojima ◽  
Ayato Takada ◽  
Hideki Ebihara ◽  
Gabriele Neumann ◽  
Kouki Fujioka ◽  
...  
Keyword(s):  
Receptor Tyrosine Kinase ◽  
Molecular Mechanisms ◽  
Family Members ◽  
Ectopic Expression ◽  
Hemorrhagic Fever ◽  
Cell Types ◽  
Lymphoid Cells ◽  
Cell Entry ◽  
A Cell ◽  
Receptor Tyrosine Kinase Family

ABSTRACT Filoviruses, represented by the genera Ebolavirus and Marburgvirus, cause a lethal hemorrhagic fever in humans and in nonhuman primates. Although filovirus can replicate in various tissues or cell types in these animals, the molecular mechanisms of its broad tropism remain poorly understood. Here we show the involvement of members of the Tyro3 receptor tyrosine kinase family—Axl, Dtk, and Mer—in cell entry of filoviruses. Ectopic expression of these family members in lymphoid cells, which otherwise are highly resistant to filovirus infection, enhanced infection by pseudotype viruses carrying filovirus glycoproteins on their envelopes. This enhancement was reduced by antibodies to Tyro3 family members, Gas6 ligand, or soluble ectodomains of the members. Live Ebola viruses infected both Axl- and Dtk-expressing cells more efficiently than control cells. Antibody to Axl inhibited infection of pseudotype viruses in a number of Axl-positive cell lines. These results implicate each Tyro3 family member as a cell entry factor in filovirus infection.

scholarly journals The Chikungunya virus nsP3 macro domain inhibits activation of the NF-κB pathway

2019 ◽  
Author(s):  
Grace C. Roberts ◽  
Nicola J. Stonehouse ◽  
Mark Harris
Keyword(s):  
Transcription Factor ◽  
Chikungunya Virus ◽  
Ectopic Expression ◽  
Cell Types ◽  
Hydrolase Activity ◽  
Structural Protein ◽  
Chikv Infection ◽  
N Terminus ◽  
Macro Domain

AbstractThe role of the chikungunya virus (CHIKV) non-structural protein 3 (nsP3) in the virus lifecycle is poorly understood. The protein comprises 3 domains. The N-terminus is a macro domain, biochemically characterised to bind both RNA and ADP-ribose, and to possess ADP-ribosyl hydrolase activity – an enzymatic activity that removes ADP-ribose from mono-ADP-ribosylated proteins. As ADP-ribosylation is important in the signalling pathway leading to activation of the transcription factor NF-κB, we sought to determine if the macro domain might perturb NF-κB signalling. We first show that CHIKV infection did not induce NF-κB activation, and could not block exogenous activation of the pathway via TNFα, although TNFα treatment did reduce virus titres. Ectopic expression of nsP3 was able to block TNFα-mediated NF-κB activation and this was dependent on the macro domain, as mutations previously shown to disrupt either ADP-ribose binding or hydrolase activity lost the ability to inhibit NF-κB activation. Lastly, we determined the phenotype of the macro domain mutants in the context of virus infection in a range of cell types. Our data are consistent with cell- and species-dependent roles of the macro domain, however, these phenotypes do not correlate with the ability to inhibit NF-κB activation suggesting that the macro domain plays multiple independent roles in the virus lifecycle.

scholarly journals Chemokine Subversion by Human Herpesviruses

2018 ◽  
Vol 10 (5-6) ◽  
pp. 465-478 ◽  
Author(s):  
Sergio M. Pontejo ◽  
Philip M. Murphy ◽  
James E. Pease
Keyword(s):  
Chemokine Receptors ◽  
Binding Proteins ◽  
Molecular Mechanisms ◽  
Human Herpesvirus ◽  
Cell Entry ◽  
Target Cells ◽  
Multiple Functions ◽  
Modulation Of Gene Expression ◽  
Human Herpesviruses ◽  
Review Current

Viruses use diverse molecular mechanisms to exploit and evade the immune response. Herpesviruses, in particular, encode functional chemokine and chemokine receptor homologs pirated from the host, as well as secreted chemokine-binding proteins with unique structures. Multiple functions have been described for herpesvirus chemokine components, including attraction of target cells, blockade of leukocyte migration, and modulation of gene expression and cell entry by the virus. Here we review current concepts about how human herpesvirus chemokines, chemokine receptors, and chemokine-binding proteins may be used to shape a proviral state in the host.

scholarly journals Emerging chikungunya virus variants at the E1-E1 inter-glycoprotein spike interface impact virus attachment and Inflammation.

2021 ◽  
Author(s):  
Margarita V. Rangel ◽  
Nicole McAllister ◽  
Kristen Dancel-Manning ◽  
Maria G. Noval ◽  
Laurie A. Silva ◽  
...  
Keyword(s):  
Human Health ◽  
Chikungunya Virus ◽  
Molecular Mechanisms ◽  
Cell Attachment ◽  
Host Cells ◽  
Chikv Infection ◽  
Virus Attachment ◽  
Pathogenic Variants ◽  
Important Region

Chikungunya virus (CHIKV) is a re-emerging arthropod-borne alphavirus and a serious threat to human health. Therefore, efforts toward elucidating how this virus causes disease and the molecular mechanisms underlying steps of the viral replication cycle are crucial. Using an in vivo transmission system that allows intra-host evolution, we identified an emerging CHIKV variant carrying a mutation in the E1 glycoprotein (V156A) in the serum of mice and saliva of mosquitoes. E1 V156A has since emerged in humans during an outbreak in Brazil, co-occurring with a second mutation, E1 K211T, suggesting an important role for these residues in CHIKV biology. Given the emergence of these variants, we hypothesized that they function to promote CHIKV infectivity and subsequent disease. Here, we show that E1 V156A and E1 K211T modulate virus attachment and fusion and impact binding to heparin, a homolog of heparan sulfate, a key entry factor on host cells. These variants also exhibit differential neutralization by anti-glycoprotein monoclonal antibodies, suggesting structural impacts on the particle that may be responsible for altered interactions at the host membrane. Finally, E1 V156A and E1 K211T exhibit increased titers in an adult arthritic mouse model and induce increased foot-swelling at the site of injection. Taken together, this work has revealed new roles for E1 where discrete regions of the glycoprotein are able to modulate cell attachment and swelling within the host. IMPORTANCE Alphaviruses represent a growing threat to human health worldwide. The re-emerging alphavirus chikungunya virus (CHIKV) has rapidly spread to new geographic regions in the last several decades, causing overwhelming outbreaks of disease, yet there are no approved vaccines or therapeutics. The CHIKV glycoproteins are key determinants of CHIKV adaptation and virulence. In this study, we identify and characterize the emerging E1 glycoprotein variants, V156A and K211T, that have since emerged in nature. We demonstrate that E1 V156A and K211T function in virus attachment to cells, a role that until now has been only attributed to specific residues of the CHIKV E2 glycoprotein. We also demonstrate E1 V156A and K211T to increase foot-swelling of the ipsilateral foot in mice infected with these variants. Observing that these variants and other pathogenic variants occur at the E1-E1 inter-spike interface, we highlight this structurally important region as critical for multiple steps during CHIKV infection. Together, these studies further defines the function of E1 in CHIKV infection and can inform the development of therapeutic or preventative strategies.

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